Sulphur-rich lichen at Devil’s Tower

Monocline in Bighorn National Forest, Wyoming

Shell Falls, Bighorn National Forest, Wyoming

Chugwater Formation, Montana

Sand Piper at Thermopolis Sulphur Hot Springs, Wyoming

Upper Falls, Yellowstone National Park

Crystal Falls, Yellowstone National Park

Beryl Spring, Yellowstone National Park

KBL Formation, Dillon, MT

Sunset at Birch Creek Center, Dillon, MT

KKL Formation, Dillon, MT

KKL Formation, Dillon, MT

KKG Formation, Block Mountain, MT

TRDU Formation, Block Mountain

KKG Formation, Block Mountain, Dillon, MT

Block Mountain, Dillon, MT

Block Mountain, Dillon MT

Block Mountain, Dillon, MT